 
(* ::Section:: *)
(* Coefficients2 *)
(* ::Text:: *)
(*Coefficient2[exp, form1, form2, ...] is like Coefficient, but it also allows to extracts coefficients  of form1, form2, ... sequentially. To specify the power in formi, write it as {var,pow}.*)


(* ::Subsection:: *)
(* Examples *)
ex=y0+ep y1+a4(1/ep x1 + x2 +x3 ep)+ a4^2(1/ep^2z1 +1/ep z2 + z3 +x4 ep)

Coefficient2[ex,a4]

Coefficient2[ex,a4,2]

Coefficient2[ex,{a4,2}]

Coefficient2[ex,{a4,2},{ep,-1}]

Coefficient2[ex,{a4,1},{ep,0}]

Coefficient2[ex,a4,ep]
